THE LOWER EXTREMITY. 1209 
over the distal half of the fourth metacarpal bone ; (3) from the proximal part of the first 
incision an opening may be made through the first interosseous Space on to the dorsum, 
care being taken to keep below the radial artery ; (4) a longitudinal incision between fe 
median and ulnar nerves, on the proximal side of the superficial palmar arch. At the 
wrist a longitudinal incision may be made immediately internal to the palmaris longus 
tendon, thus falling between the line of the median nerve and the ulnar artery. To open 
the digital flexor sheaths, incisions are made along the middle of the palmar surface of the 
fingers opposite the first and second phalanges. The collateral digital vessels and nerves 
descend along the lateral aspects of the fingers, nearer the flexor than the extensor 
surfaces. In cutting down upon the dorsal aspects of the phalanges, the incisions should 
be made to one or other side of the extensor tendon, preferably upon the ulnar side, to 
avoid division of the insertions of lumbrical muscles. The subcutaneous tissue of the 
palmar. aspect of the terminal phalanges is connected by fibrous processes with the 
periosteum ; hence the frequency of necrosis of the terminal phalanx in suppurative 
inflammations in this region. 
THE LOWER EXTREMITY. 
THE BUTTOCK. 
The region of the hip or buttock extends from the crest of the ilium above to 
the gluteal fold below. The highest point of the iliac crest, situated a little behind 
its middle, i is on a level with the fourth lumbar spine; the anterior superior spine 
of the ilium is directed forwards, and belongs to the groin, which it limits exter- 
nally ; the posterior superior spine, situated at the bottom of a dimple or small 
depression, is on a level with the second sacral spine, and corresponds, therefore, to 
the middle of the sacro-iliac joint. Two and a half inches behind the anterior 
superior spine is a prominence upon the outer lip of the iliac crest; this pro- 
minence, which is termed the tubercular point, is the most external part of the crest, 
and will be again referred to in dealing with the surface anatomy of the abdomen. 
A hand’s breadth below the tubercle of the crest is the great trochanter of the 
femur, the most external bony landmark of the hip; its anterior and posterior 
borders are best felt between the fingers and thumb, while the limb is shehtly 
abducted to relax the ilio-tibial band, and if the thigh be now rotated, 1t will be 
noted that the trochanter rotates around the seoment of a circle, the radius of 
which is formed by the head and neck of the femur; in non-impacted fractures of 
the neck of the femur the trochanter rotates around the segment of a much 
smaller circle. MNelaton’s line, drawn from the anterior superior spine to the most 
prominent part of the ischial tuberosity, crosses the hip at the level of the upper 
border of the great trochanter; this line is employed to ascertain the presence 
or absence of upward displacement of the trochanter. Chiene demonstrates the 
relative height of the trochanters by stretching two tapes across the front of 
the pelvis, one between the anterior superior spines, and the other between the 
upper borders of the trochanters; the lower tape will converge towards the upper 
on the side of the upward displacement. A line prolonging the anterior border of 
the great trochanter vertically upwards touches the iliac crest at the tubercular 
point. The ischial tuberosity, in the erect posture, is overlapped by the lower 
border of the gluteus maximus; its most prominent part is felt a little above the 
inner part of the gluteal fold. If the hip be rotated inwards, the lesser trochanter 
of the femur may be felt by deep palpation above the outer end of the gluteal 
fold; it corresponds to the interval between the lower border of the quadratus 
femoris and the upper border of the adductor magnus, and therefore, also, to the 
level of the internal circumflex artery. 
The lower border of the gluteus maximus lies a little above the gluteal fold inter- 
nally, crosses it about its middle, and is continued downwards and outwards to 
meet the upper end of the furrow of the external intermuscular septum, at the 
junction of the upper and middle thirds of the femur. The inner borders of the 
two great gluteal muscles are separated by the deep gluteal cleft, which extends 
upwards and backwards from the perineum to the level of the fourth sacral spine, 
where it opens out into the triangle upon the back of the sacrum. Anteriorly the 
buttock is limited by the prominence of the tensor fascie femoris muscle, which 
